Diaphragm manhole for tanks



Aug. 11, 1925.

L. H. HILL ET AL DIAPHRAGM MANHOLE FOR TANKS Filed Dec. 2:. 1922 Fig. 1..

Egg 3 I wrrmzssas:

INVENTORS Leland Hill &

WaHer Darlrl.

ATTORNEY Patented Aug. 11, 1925,

UN-l'liE-D STATES PATENT OFFKlE.

LELAND H. HILL AND WALTER M. DANN, 0F WILKINSB'URG, PENNSYLVANIA, AS- SIGNORS T0 WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A COR- PORATION OF PENNSYLVANIA.

DIAPHRAGM MANHOLE FOR TANKS.

Application filed; December 23, 1922. Serial No. 608,773.

To all whom it may concern:

Be it known that we, LELAND H. H m, a citizen of the United States, and a resident o1 Wilkinsburg, in the county of Allegheny and State of Pennsylvania, and l/VALTER M. DANN, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful llmprovementin Diaphragm Manholes for lljanks, of which the following 'is a specification.

@ur invention relates to diaphragm manholes for tanks, and it has particular relation to such tanks as are employed in connection with transformers, circuit breakers and similar apparatus,

One object of our invention is to provide a diaphragm of such strength as to yield easily upon the occurrence of sudden pressure, but which is of suflicient strength to remain intact during the normal operation of the device with which it is associated.

A second object of our invention is to provide a structure for protecting a relatively thin diaphragm from mechan1 cal injury, but which is readily yleldable in case the diaphragm is ruptured by abnormal pressures.

It may occur, in the operation of transformers, circuit breakers and similar apparatus, that an explosive mixture may be formed therein or a sudden evolution of gases may occur by reason of an are or of a fault below the level of the oil for covering the electrical apparatus.

It has been found also that it is undesirable to place the diaphragm at the end of a comparatively long pipe because the column of air in the pi e ofi'ers sufficient resistanceby reason of its inertia that, if the explosions occurring in the tank have a relatively steep wave front, the stresses may be suflicient to separate the parts of the tank before the diaphragm operates.

In accordance with the present invention, we have provided adiaphragm of relatively thin material that is located substantially in alin men t he surface f the manhole or cover of the tank. Suitable means are provided for protecting the diaphragm from external injury, the protecting means being of such character as to yield readily upon the occurrence of excessive pressure in order not to impede the flow of gas from the tank.

in the accompanying drawing,

Figure 1 is a side view in elevation of a transformer tank with our invention applied thereto; and p I Fig. 2 is an enlarged sectional view of a portion of the tank with the manhole cover and the diaphragm in operative position thereon.

A. tank 1, for enclosing a transformer, circuit' breaker or other apparatus, is provided with an opening 2, that is normally covered by a structure shown in detail in Fig. 2, The structure for covering the opening 2 comprises an annular member 3" that is adapted to be secured to the top of the tank by threaded studs 4;.

The member 3 is provided with a recessed portion on its lower side to receive a relatively thin diaphragm 5, which may be, for example, of insulating material known as micarta, or other material of suitable tensile strength. A gasket 6 is placed between the diaphragm 5 and the tank 1 for the purpose of insuring an air-tight joint therebetween. The top of the annular member 3 is covered by a member 7 provided with holes 8, through which the studs 4 extend. These holes are of such diameter that the member 7 may move freely thereon. The studs 4 are of such length that the cover member 7 may move through a considerable distance to relieve pressure that may be transmitted through the diaphragm 5 when the latter has been ruptured. Each of the studs 4 is surrounded by a relatively light spring 9 for the purpose of cushioning the blow transmitted by the cover member 7, in case it is lifted by explosions occurring within the tank.

It may be assumed that the transformer which is specified by way of example only is in operation and that a fault occurs in the apparatus under the insulating oil. lt may be assumed further that the fault 1s of such character as to cause a sudden evolution of a large volume of gases by reason of the breaking down of the oil. The formation of the gases at a relatively high rate causesa rupture of the diaphragm 5 and the transmission of the pressure to the cover member 7. The latter is lifted to the limit permitted by the nuts 10 on the outer ends of the studs 4 to permit the escape of gases under excessive pressure within the tank 1. When the pressure within the tank is sufliciently reduced, the cover member 7 assumes its normal position in engagement with a gasket 11 to protect the apparatus and insulating oil from contact with the external atmosphere.

The advantages of a device constructed in accordance with ourinvention are that, during the normal operation of the apparatus, the diaphragm efiectively isolates the oil and gases within the transformer from the atmosphere. The tensile strength of the diaphragm is such as to resist changes in pressure caused by the normal operation of of the apparatus. It is sufiiciently weak, however, to be ruptured upon the occurrence of abnormal pressures within the tank. The diaphragm is eflectually protectedfrom accidental damage and from the weather by an arrangement which does not, in any way, affect the utility of the diaphragm.

A saving is effected also in that the diaphragm is combined with the manhole cover whereby a single opening in the top of the tank 1 is required. This is an advantage by reason of the fact that only a limited space is available on the top of the modern transformer.

We claim as our invention 1. The combination with a tank having an opening therein, of means for covering said opening comprising a diaphragm and a loosely mounted member for covering said diaphragm, and adjustable means for limiting the movement of said member outwardly from said tank.

2. The combination with a tank having an inwardly within predetermined limits when said diaphragm is ruptured by pressure within the tank.

4. The combination with a tank having a manhole therein, of a cover for said manhole comprising a member detaehably connected to said tank and a diaphragm for sealing the manhole carried by said member, and a cover member for said diaphragm that is normally adjacent to, and supported by, said detachably connected member, said cover member belng .loosely mounted for successive and equal outward and inward movements upon the rupture of said diaphragm.

5. The combination with a tank having a manhole, of cover means for said manhole comprising an annular member bolted thereto, a diaphragm carried by said member and disposed adjacent to said tank for clos- "ing said manhole, and a cover member for said diaphragm that is loosely mounted for limited outward movement and equal in ward1 movement when the diaphragm is rupture 6. The combination with a container having an opening therein and a diaphragm for closing said opening, of a cover member for normally isolating said diaphragm from the atmosphere and yielding means for permitting limited outward and return movements of said cover member upon the rupture of said diaphragm.

7. The combination with a container having an opening therein and a diaphragm for closing said opening, of a cover member for normally isolating said diaphragm from the atmosphere and means whereby said cover member may move outwardly from its normal position Within predetermined limits and may be returned to its normal position by force of gravity.

8. The combination with a container having an opening therein and a diaphragm for closing said opening, of a cover member for normally isolatingsaid diaphragm from the atmosphere and means whereby said cover member is permitted to move outwardly from its normal position and return thereto, said means comprising guide members for said cover member having means for limiting the extent of its outward movement.

9. The combination with a container having an opening therein and a diaphragm for closing said opening, of a cover member for normally isolating said diaphragm from the atmosphere and means whereby said cover member is permitted to move outwardly from its normal position andreturn thereto, said means comprising rods or bolts coacting with recesses to guide said cover member and springs for yleldingly limiting its outward movement.

10. The combination with a container having an opening therein and a diaphragm for closing said opening, of a cover member for normally lsolatmg said diaphragm from the atmosphere and means whereby said cover member is permitted to move outwardly from its normal position and return thereto, said means comprising guide members, adjustable means carried thereby for limiting the outward movement and springs on said guide members for cushioning the impact of said cover member. 7

In testimony whereof, We have hereunto subscribed our names this 21st day of December, 1922.

LELAND H. HILL. WALTER M. DANN. 

